A 3% house edge vs. skillful play is a number I have heard kicked around several times on the net. I vaguely recall seeing a reputable analyst post this number -- about a year ago I considered analyzing the game myself and gave up after reading something that convinced me it was impossible to beat -- but I can't find it again.
The 3% number can be found in various articles discussing the game's manufacturer peddling it at trade shows, for instance
http://grochowski.casinocitytimes.co...les/16348.html - but can't find the source for the actual number.